Bridgeless interleaved power factor corrector and method of controlling the same

Abstract

A bridgeless interleaved power factor corrector is used to convert an AC power source into a DC power source. The bridgeless interleaved power factor corrector includes a first conversion circuit, a second conversion circuit, a first power switch, a second power switch, a positive-half control switch, and a negative-half control switch. The first power switch is coupled to one of two positive-half operation units of the first conversion circuit and one of two negative-half operation units of the second conversion circuit. The second power switch is coupled to the other one of two positive-half operation units and the other one of two negative-half operation units. The positive-half control switch is coupled between a neutral end and a ground end, and the negative-half control switch is coupled between a line end and the ground end.

What is claimed is: 
     
       1. A bridgeless interleaved power factor corrector (PFC) adapted to convert an AC power source into a DC power source, the bridgeless interleaved PFC comprising:
 a first conversion circuit coupled to a line end of the AC power source and comprising two positive-half operation units, the two positive-half operation units coupled to a positive voltage end with respect to a ground end; 
 a second conversion circuit coupled to a neutral end of the AC power source and in parallel connection with the first conversion circuit, the second conversion circuit comprising two negative-half operation units coupled to the positive voltage end; 
 a first power switch coupled to one of the two positive-half operation units and one of the two negative-half operation units, and wherein the first power switch is disposed between the one of the two positive-half operation units and the ground end and disposed between the one of the two negative-half operation units and the ground end; 
 a second power switch coupled to the other one of the two positive-half operation units and the other one of the two negative-half operation units, and where the second power switch is disposed between the other one of the two positive-half operation units and the ground end and disposed between the other one of the two negative-half operation units and the ground end; 
 a positive-half control switch coupled between the neutral end and the ground end; and 
 a negative-half control switch coupled between the line end and the ground end. 
 
     
     
       2. The bridgeless interleaved PFC in  claim 1 , further comprising:
 an output capacitance coupled between the positive voltage end and the ground end, and providing the DC power source. 
 
     
     
       3. The bridgeless interleaved PFC in  claim 2 , wherein the two positive-half operation units comprises a first positive-half operation unit and a second positive-half operation unit,
 the first positive-half operation unit comprising: 
 a first diode; 
 a second diode coupled to the first diode to form a first parallel branch, the first parallel branch coupled to the positive voltage end and the first power switch; and 
 a first inductor in serial connection with the first parallel branch; 
 the second positive-half operation unit comprising: 
 a third diode; 
 a fourth diode coupled to the third diode to form a second parallel branch, the second parallel branch coupled to the positive voltage end and the second power switch; and 
 a second inductor in serial connection with the second parallel branch; 
 wherein the two negative-half operation units comprises a first negative-half operation unit and a second negative-half operation unit; 
 the first negative-half operation unit comprising: 
 a fifth diode; 
 a sixth diode coupled to the fifth diode to form a third parallel branch, the third parallel branch coupled to the positive voltage end and the first power switch; and 
 a third inductor in serial connection with the third parallel branch; 
 the second negative-half operation unit comprising: 
 a seventh diode; 
 an eighth diode coupled to the seventh diode to form a fourth parallel branch, the fourth parallel branch coupled to the positive voltage end and the second power switch; and 
 a fourth inductor in serial connection with the fourth parallel branch. 
 
     
     
       4. The bridgeless interleaved PFC in  claim 3 , wherein a cathode of the second diode, a cathode of the fourth diode, a cathode of the sixth diode, a cathode of the eighth diode are coupled to the positive voltage end; a cathode of the first diode and a cathode of the fifth diode are coupled to a non-ground end of the first power switch; a cathode of the third diode and a cathode of the seventh diode are coupled to a non-ground end of the second power switch. 
     
     
       5. The bridgeless interleaved PFC in  claim 3 , when the AC power source is in positive-half operation, the positive-half control switch is turned on, the negative-half control switch is turned off, the first power switch and the second power switch are switched between turning on and turning off; when the AC power source is in negative-half operation, the positive-half control switch is turned off, the negative-half control switch is turned on, the first power switch and the second power switch are switched between turning on and turning off. 
     
     
       6. The bridgeless interleaved PFC in  claim 5 , wherein
 when the positive-half control switch is turned on and the first power switch is turned on, the first diode is turned on and the first inductor is in energy-storage operation; when the positive-half control switch is turned on and the second power switch is turned on, the third diode is turned on and the second inductor is in energy-storage operation; and 
 when the negative-half control switch is turned on and the first power switch is turned on, the fifth diode is turned on and the third inductor is in energy-storage operation; and when the negative-half control switch is turned on and the second power switch is turned on, the seventh diode is turned on and the fourth inductor is in energy-storage operation. 
 
     
     
       7. The bridgeless interleaved PFC in  claim 5 , wherein
 when the positive-half control switch is turned on and the first power switch is turned off, the second diode is turned on and the first inductor is in energy-release operation; when the positive-half control switch is turned on and the second power switch is turned off, the fourth diode is turned on and the second inductor is in energy-release operation; and 
 when the negative-half control switch is turned on and the first power switch is turned off, the sixth diode is turned on and the third inductor is in energy-release operation; and 
 
       when the negative-half control switch is turned on and the second power switch is turned off, the eighth diode is turned on and the fourth inductor is in energy-release operation. 
     
     
       8. The bridgeless interleaved PFC in  claim 6 ,
 when the first inductor is in energy-storage operation, the line end, the first inductor, the first diode, the first power switch, the ground end, the positive-half control switch and the neutral end form a first energy-storage path; 
 when the second inductor is in energy-storage operation, the line end, the second inductor, the third diode, the second power switch, the ground end, the positive-half control switch and the neutral end form a second energy-storage path; 
 when the third inductor is in energy-storage operation, the neutral end, the third inductor, the fifth diode, the first power switch, the ground end, the negative-half control switch and the line end form a third energy-storage path; and 
 when the fourth inductor is in energy-storage operation, the neutral end, the fourth inductor, the seventh diode, the second power switch, the ground end, the negative-half control switch and the line end form a fourth energy-storage path. 
 
     
     
       9. The bridgeless interleaved PFC in  claim 7 ,
 when the first inductor is in energy-release operation, the first inductor, the second diode, the output capacitance, the ground end, the positive-half control switch, the neutral end, and the line end form a first energy-release path; 
 when the second inductor is in energy-release operation, the second inductor, the fourth diode, the output capacitance, the ground end, the positive-half control switch, the neutral end, and the line end form a second energy-release path; 
 when the third inductor is in energy-release operation, the third inductor, the sixth diode, the output capacitance, the ground end, the negative-half control switch, the line end, and the neutral end form a third energy-release path; and 
 when the fourth inductor is in energy-release operation, the fourth inductor, the eighth diode, the output capacitance, the ground end, the negative-half control switch, the line end, and the neutral end form a fourth energy-release path. 
 
     
     
       10. A method for controlling bridgeless interleaved power factor corrector (PFC), the bridgeless interleaved PFC converting an AC power source into a DC power source and the bridgeless interleaved PFC comprising a first conversion circuit coupled to a line end of the AC power source, a second conversion circuit coupled to a neutral end of the AC power source, a first power switch and a second power switch coupled between the first conversion circuit, the second conversion circuit and the ground end, a positive-half control switch coupled between the neutral end and the ground end and a negative-half control switch coupled between the line end and the ground end, the method comprising:
 (a) when the AC power source is in positive-half operation, turning on the positive-half control switch and turning off the negative-half control switch; 
 (b) turning on the first power switch to render a first inductor in the first conversion circuit to conduct energy-storage operation; turning on the second power switch to render a second inductor in the first conversion circuit to conduct energy-storage operation; 
 (c) when the AC power source is in negative-half operation, turning off the positive-half control switch and turning on the negative-half control switch; and 
 (d) turning on the first power switch to render a third inductor in the second conversion circuit to conduct energy-storage operation; turning on the second power switch to render a fourth inductor in the second conversion circuit to conduct energy-storage operation. 
 
     
     
       11. The method in  claim 10 , wherein the step (b) further comprises:
 (b′) turning off the first power switch to render the first inductor to conduct energy-release operation; turning off the second power switch to render the second inductor to conduct energy-release operation; 
 wherein the step (d) further comprises: 
 (d′) turning off the first power switch to render the third inductor to conduct energy-release operation; turning off the second power switch to render the fourth inductor to conduct energy-release operation. 
 
     
     
       12. The method in  claim 10 , further comprising:
 providing two positive-half operation units in the first conversion circuit and coupling the two positive-half operation units to a positive voltage end with respect to the ground end; 
 providing two negative-half operation units in the second conversion circuit and coupling the two negative-half operation units to the positive voltage end; 
 coupling the first power switch to one of the two positive-half operation units and one of the two negative-half operation units and disposing the first power switch between the one of the two positive-half operation units and the ground end and disposing the first power switch between the one of the two negative-half operation units and the ground end; 
 coupling the second power switch to the other one of the two positive-half operation units and the other one of the two negative-half operation units and disposing the second power switch between the other one of the two positive-half operation units and the ground end and disposing the second power switch between the other one of the two negative-half operation units and the ground end. 
 
     
     
       13. The method in  claim 12 , further comprising:
 providing an output capacitance coupled between the positive voltage end and the ground end and the output capacitance providing the DC power source. 
 
     
     
       14. The method in  claim 13 , wherein the two positive-half operation units comprises a first positive-half operation unit and a second positive-half operation unit, the first positive-half operation unit comprising:
 a first diode; 
 a second diode coupled to the first diode to form a first parallel branch, the first parallel branch coupled to the positive voltage end and the first power switch; and 
 a first inductor in serial connection with the first parallel branch; 
 the second positive-half operation unit comprising: 
 a third diode; 
 a fourth diode coupled to the third diode to form a second parallel branch, the second parallel branch coupled to the positive voltage end and the second power switch; and 
 a second inductor in serial connection with the second parallel branch; 
 the two negative-half operation units comprises a first negative-half operation unit and a second negative-half operation unit; 
 the first negative-half operation unit comprising: 
 a fifth diode; 
 a sixth diode coupled to the fifth diode to form a third parallel branch, the third parallel branch coupled to the positive voltage end and the first power switch; and 
 a third inductor in serial connection with the third parallel branch; 
 the second negative-half operation unit comprising: 
 a seventh diode; 
 an eighth diode coupled to the seventh diode to form a fourth parallel branch, the fourth parallel branch coupled to the positive voltage end and the second power switch; and 
 a fourth inductor in serial connection with the fourth parallel branch. 
 
     
     
       15. The method in  claim 14 , wherein a cathode of the second diode, a cathode of the fourth diode, a cathode of the sixth diode, a cathode of the eighth diode are coupled to the positive voltage end; a cathode of the first diode and a cathode of the fifth diode are coupled to a non-ground end of the first power switch; a cathode of the third diode and a cathode of the seventh diode are coupled to a non-ground end of the second power switch. 
     
     
       16. The method in  claim 14 , when the AC power source is in positive-half operation, the positive-half control switch is turned on, the negative-half control switch is turned off, the first power switch and the second power switch are switched between turning on and turning off; when the AC power source is in negative-half operation, the positive-half control switch is turned off, the negative-half control switch is turned on, the first power switch and the second power switch are switched between turning on and turning off. 
     
     
       17. The method in  claim 16 , when the positive-half control switch is turned on and the first power switch is turned on, the first diode is turned on and the first inductor is in energy-storage operation; when the positive-half control switch is turned on and the second power switch is turned on, the third diode is turned on and the second inductor is in energy-storage operation; and
 when the negative-half control switch is turned on and the first power switch is turned on, the fifth diode is turned on and the third inductor is in energy-storage operation; and when the negative-half control switch is turned on and the second power switch is turned on, the seventh diode is turned on and the fourth inductor is in energy-storage operation. 
 
     
     
       18. The method in  claim 16 , wherein
 when the positive-half control switch is turned on and the first power switch is turned off, the second diode is turned on and the first inductor is in energy-release operation; when the positive-half control switch is turned on and the second power switch is turned off, the fourth diode is turned on and the second inductor is in energy-release operation; and 
 when the negative-half control switch is turned on and the first power switch is turned off, the sixth diode is turned on and the third inductor is in energy-release operation; when the negative-half control switch is turned on and the second power switch is turned off, the eighth diode is turned on and the fourth inductor is in energy-release operation. 
 
     
     
       19. The method in  claim 17 , wherein
 when the first inductor is in energy-storage operation, the line end, the first inductor, the first diode, the first power switch, the ground end, the positive-half control switch and the neutral end form a first energy-storage path; 
 when the second inductor is in energy-storage operation, the line end, the second inductor, the third diode, the second power switch, the ground end, the positive-half control switch and the neutral end form a second energy-storage path; 
 when the third inductor is in energy-storage operation, the neutral end, the third inductor, the fifth diode, the first power switch, the ground end, the negative-half control switch and the line end form a third energy-storage path; and 
 when the fourth inductor is in energy-storage operation, the neutral end, the fourth inductor, the seventh diode, the second power switch, the ground end, the negative-half control switch and the line end form a fourth energy-storage path. 
 
     
     
       20. The method in  claim 18 , wherein
 when the first inductor is in energy-release operation, the first inductor, the second diode, the output capacitance, the ground end, the positive-half control switch, the neutral end, and the line end form a first energy-release path; 
 when the second inductor is in energy-release operation, the second inductor, the fourth diode, the output capacitance, the ground end, the positive-half control switch, the neutral end, and the line end form a second energy-release path; 
 when the third inductor is in energy-release operation, the third inductor, the sixth diode, the output capacitance, the ground end, the negative-half control switch, the line end, and the neutral end form a third energy-release path; and 
 when the fourth inductor is in energy-release operation, the fourth inductor, the eighth diode, the output capacitance, the ground end, the negative-half control switch, the line end, and the neutral end form a fourth energy-release path.